8170660721 has 2 divisors, whose sum is σ = 8170660722. Its totient is φ = 8170660720.

The previous prime is 8170660711. The next prime is 8170660741. The reversal of 8170660721 is 1270660718.

8170660721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7843050721 + 327610000 = 88561^2 + 18100^2 .

It is a cyclic number.

It is not a de Polignac number, because 8170660721 - 2³⁰ = 7096918897 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (8170660711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4085330360 + 4085330361.

It is an arithmetic number, because the mean of its divisors is an integer number (4085330361).

Almost surely, 2^8170660721 is an apocalyptic number.

It is an amenable number.

8170660721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8170660721 is an equidigital number, since it uses as much as digits as its factorization.

8170660721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 8170660721 is about 90391.7071472820. The cubic root of 8170660721 is about 2014.1217797327.

The spelling of 8170660721 in words is "eight billion, one hundred seventy million, six hundred sixty thousand, seven hundred twenty-one".